Herbicidal method employing arylthiohydramic acids

ABSTRACT

Herbicidal compositions containing as the herbicidally active ingredient an aromatic thiohydroxamic acid and herbicidal methods employing such compositions are disclosed. Benzothiohydroxamic acids are useful in controlling undesirable vegetation.

United States Patent 1 Franz Nov. 6, 1973 HERBICIDAL METHOD EMPLOYINGARYLTHlOl-IYDRAMIC ACIDS [52] US. Cl. 71/98, 260/5005 H [51] Int. ClA01n 9/12 [58] Field of Search 71/98, 118;

\ [56] References Cited UNITED STATES PATENTS 3,236,871 2/1966 Hinman etal 260/5005 H 3,123,460 3/1964 Schafer et al 71/98 2,936,323 5/1960 Eden71/118 2,412,510 12/1946 Jones 71/98 2,577,969 12/1951 Jones 71/1183,268,539 8/1966 Levy 260/453 R FOREIGN PATENTS OR APPLICATIONS 21,5003/1966 Japan 71/98 OTHER PUBLICATIONS Bacchetti et al., ThiohydroxamicAcids, etc., (1958) CA 52 p. 18299 (1958).

Hase et al., inhibition of P. Vulgaris Veease etc.; (1967) CA 67 No.105516; (1967).

Primary Examiner-Glennon H. Hollrah Att0rney-Neal E. Willis et al.

[57] ABSTRACT Herbicidal compositions containing as the herbicidallyactive ingredient an aromatic thiohydroxamic acid and herbicidal methodsemploying such compositions are disclosed. Benzothiohydroxamic acids areuseful in controlling undesirable vegetation.

4 Claims, No Drawings .HERBICIUAL METHOD EMPLOYING ARYLTHIOHYDRAMICACIDS This invention is related to new herbicidal compositions and tonew herbicidal methods. More particularly this invention relates tomethods of controlling growing vegetation by applying thereto aherbicidally effective amount of an aromatic thiohydroxamic acid.

In accordance with this invention, it has been found that the growth ofemerging seedlings and established vegetation can be controlled andmodified by exposing the emerging seedlings or above-ground portions ofestablished vegetation to the action of a herbicidally effective amountof one or more aromatic thiohydroxamic acid of the formula NOH wherein Ris an aryl group of from six to carbon atoms or said aryl groupsubstituted with a lower alkyl, a halogen or nitro group.

Illustrative of the aryl groups represented by R are for example phenyland naphthyl. Illustrative of the lower alkyl substituted aryl groupsrepresented by R are, for example, tolyl, xylyl, ethylphenyl,butylphenyl, diethylphenyl, trimethylphenyl and the like. The term haloas employed herein means chlorine, fluorine, bromine or iodine. Thesubstituted aryl groups represented by R can-contain from 1 to 3 of theabove substituents and said substituents need not be the same.

The herbicidal compositions of this invention contain at least oneactive ingredient and a material referred to in the art as a herbicidaladjuvant in liquid or solid form. The herbicidal compositions areprepared by ad mixing the active ingredient with an adjuvant includingdiluents, extenders, carriers and conditioning agents to providecompositions in the form of finely-divided particulate solids, granules,pellets, solutions and aqueous dispersions or emulsions.

Typical finely-divided solid carriers and extenders which can be used inthe herbicidal compositions of this invention include but are notlimited to talcs; clays, pumice, silica, diatomaceous earth, vquartz,Fullers earth, powdered cord, powdered wood, walnut flour; chalk,tobacco dust, volcanic ash and the like. Typical liquid diluents includebut is not limited to'kerosene, Stoddard solvent, hexane, benzene,toluene, acetone, ethylene dichloride, xylene, alcohols, diesel oil,glycols and the like. a

The herbicidal compositions of this invention, particularly liquids andwettable particles, usually contain as a conditioning agent one or moresurface-active agents in amounts sufficient to render a givencomposition readily dispersible in water or oil. By the termsurfaceactive agent" it is understood that wetting agents, dispersingagents, suspending agents and emulsifying agents are included therein.

The term herbicidal compositions as used herein and in the appendedclaims is intended to mean not only compositions in a suitable form forapplications but also concentrated compositions whichrequire dilution orextension with a suitable quantity of liquid or solid adjuvant prior toapplication.

By the term active ingredient as employed herein is meant the aromatichydroxamic acid.

' A Canada Thistle The aromatic thiohydroxamic acids which are employedin the herbicidal methods and compositions of this invention areproduced in accordance with the following general procedure which forthe sake of simplicity gives the preparation of benzothiohydroxamicacid:

A solution of benzohydroxamoyl chloride (6.3 g. 0.04 mole) dissolved inethanol mls) was added slowly with stirring to a solution of sodiumhydrosulfide NaSH (ll grams) dissolved in water (200 ml). Thetemperature of the mixture rose due to the exothermic heat of reactionduring which time an oily phase developed. After approximately :4 hourthe mixture was extracted with ether, and the ethereal solutiondiscarded. The aqueous phase was acidified to a pH of l withhydrochloric acid while purging the solution with nitrogen to sweep outthe liberated hydrogen sulfide. The precipitated oil was extracted withdiethyl ether and the organic solution washed with water. After dryingover anhydrous sodium sulfate, the solution was decanted, the solventremoved at reduced pressure and was then extracted with petroleum etherto yield benzothiohydroxamic acid NOH 3,4-dichlorobenzothiohydroxamicacid mp 104- 1 05C 4-nitrobenzothiohydroxamic acid mp lll.5l 13.5C3-chlorobenzothiohydroxamic acid Naphthathiohydroxamic acid2,4-dimethylbenzothiohydroxamic acid2-methyl-4-chlorobenzothiohydroxamic acid The post-emergent phytotoxicactivity of various methods of this invention is demonstrated asfollows. The active ingredients are applied in spray form to 14- day, or21-day old specimens of the plant species listed. The spray, anaqueous-organic solvent containing active ingredient, is applied to theplants in different sets of pans at several rates of active ingredientper acre. The treated plants are placed in a greenhouse and the effectsareobserved and recorded after approximately 14 days or approximately 28days, as is indicated in Table I.

The post-emergent phytotoxic acitivity index used in Table l is measuredby the average percent control of each plant species and is defined asfollows:

, N u m erical Phytotoxicity Scale None 0 Slight I Moderate 2 Severe 3Dead (kill) 4 The following list of plants are those listed in Table Iunder the given letters:

M Crab Grass B Nutsedge N Pigweed C Morning Glory Soybean D Wild Oats PWild Buckwheat E Brome Grass 0 Tomato F Rye Grass R Sorghum G Radish SRice H Sugar Beets T Smartweed l Quackgrass U Coeklebur J Johnson GrassK Foxtail L Barnyard Grass V Lambsquarter W Hemp sesbania X Wheat YVelvet Leaf TABLE 1 Compound Cont A B l) E F G H 1 J K L M N O I Q R S'l U W X Y I l O 2 0 2 0 O l .3 l l .5 2 O O O 1 3 O U 1 Z (l .3 1.... 01 2 1 O O 1. 3 2 l) (I ll (l 0 3 1 1 2 .2 2 l 3 0 0 ll 0 1 1 l 3 l 1 1 0.2 1 l l O l 0 0 0 l (l .l U 1 ill NOTE.O.5 is equivalent to between 9and 10 pounds per acre and 9.2 is about 4 pounds per acre.

As mentioned hereinbefore the phytotoxic compositions of this inventioncomprise an active ingredient and one or more adjuvants which can besolid or liquid extenders, carriers, diluents, conditioning agents andthe like. Preferred phytotoxicant compositions of this invention havebeen developed so that the active ingredients can be used to thegreatest advantage to modify the growth of plants. The preferredcompositions comprise wettable powders, aqueous suspensions, dustformulations, granules, emulsifiable oils and solutions in solvents. Ingeneral, these preferred compositions can all contain one or moresurface-active agents.

Surface-active agents which can be used in the phytotoxic compositionsof this invention are set out, for example, in Searle US. Pat. No.2,426,417, Todd US Pat. No. 2,655,447, Jones U.S. Pat. No. 2,412,510 andLenher US. Pat. No. 2,139,276. A detailed list of such agents is alsoset forth by .l. W. McCutcheon in Soap and Chemical Specialties,"November 1947, page 81 1 et seq., entitled Synthetic Detergents,Detergents and Emulsifiers Up to Date (1960), by .l. W. McCutcheon,Inc., and Bulletin E-607 of the Bureau of Entomology and PlantQuarantine of the U.S.D.A. In general, less than 50 parts by weight ofthe surface active agent is present per 100 parts by weight of plantgrowth regulant composition.

wettable powders are water-dispersible compositions containing one ormore active ingredients, an

inert solid extender and one or more wetting and dispersing agents. Theinert solid extenders are usually of mineral origin such as the naturalclays, diatomaceous earth and synthetic minerals derived from silica andthe like. Examples of such extenders include kaolinites, attapulgiteclay and synthetic magnesium silicate.

Preferred wetting agents are alkyl benzene and alkyl naphthalenesulfonates, sulfated fatty alcohols, amines or acid amides, long chainacid esters of sodium isothionate, esters of sodium sulfosuccinate,sulfated or sulfonated fatty acid esters, petroleum sulfonates,sulfonated vegetable oils, ditertiary acetylinic glycols,polyoxyethylene derivatives of alkylphenols (particularly isooctylphenoland nonylphenol) and polyoxyethylene derivatives of the mono-higherfatty acid esters of hexitol anhydrides (e.g. sorbitan). Preferreddispersants by weight of wetting agent, from about 0.25 to 25 parts byweight of dispersant and from 4.5 to about 94.5 parts by weight of inertsolid extender, all parts being by weight of the total composition.Where required from about 0.l to 2.0 parts by weight of the solid inertextender can be replaced by a corrosion inhibitor or anti-foaming agentor both.

Aqueous suspensions can be prepared by mixing together and grinding anaqueous slurry of waterinsoluble active ingredient in the presence ofdispersing agents to obtain a concentrated slurry of very finelydividedparticles. The resulting concentrated aqueous suspension ischaracterized by its extremely small particle size, so that when dilutedand sprayed coverage is very uniform.

Dusts are dense finely-divided particulatelcompositions which areintended for application to the soil in dry form. Dusts arecharacterized by their free-flowing and rapid settling properties sothat they are not readily wind-borne to areas where they are of novalue. Dusts contain primarily an active ingredient and a dense,free-flowing finely-divided particulate extender. However, theirperformance is sometimes aided by the inclusion of a wetting agent suchas those listed hereinbefore under wettable powder compositions andconvenience in manufacture frequently demands the inclusion of an inert,absorptive grinding aid. Suitable classes of grinding aids are naturalclays, diatomaceous.

earth and synthetic minerals derived from silica or silicate. Preferredgrinding aids include attapulgite clay, diatomaceous silica, syntheticfine silica and synthetic calcium and magnesium silicates.

The inert finely-divided solid extender for the dusts can be either ofvegetable or mineral origin. The solid extenders are characterized bypossessing relatively low surface areas and are poor in liquidabsorption.

Suitable inert solid extenders for plant growth regulant dusts includemicaceous talcs, pyrophyllite, dense kaolin clays, ground calciumphosphate rock and tobacco dust. The dusts usually contain from about0.5 to parts active ingredient, O to 50 parts grinding aid, 0 to 50parts wetting agent and 5 to 99.5 parts dense solid extender, all partsbeing by weight and based on the total weight of the dust.

The wettable powders described above may also be used in the preparationof dusts. While such wettable powders could be used directly in dustform, it is more advantageous to dilute them by blending with the densedust diluent. In this manner, dispersing agents, corrosion inhibitors,and anti-foam agents may also be found as components of a dust.

Emulsifiable oils are usually solutions of active ingredient inwater-immiscible or partially water-immiscible solvents together with asurface active agent. Suitable solvents for the active ingredient ofthis invention include hydrocarbpns and water-immiscible ethers, estersor ketones. Suitable surface active agents are anionic, cationic andnon-ionic such as alkyl aryl polyethoxy alcohols, polyethylene sorbitolor sorbitan fatty acid esters, polyethylene glycol fatty esters, fattyalkyllol amide condensates, amine salts of fatty alcohol sulfatestogether with long chain alcohols and oil soluble petroleum sulfonatesor mixtures thereof. The emulsifiable oil compositions generally containfrom about 5 to 95 parts active ingredient, about 1 to 50 parts surfaceactive agent and about 4 to 94 parts solvent, all parts being by weightbased on the total weight of emulsifiable oil.

Granules are physically stable particulate compositions comprisingactive ingredient adhering to or distributed through a basic matrix ofan inert, finelydivided particulate extender. in order to aid leachingof the active ingredient from the particulate, a surface active agentsuch as those listed hereinbefore under wettable powders can be presentin the composition. Natural clays, pyrophyllites, illite and vermiculiteare examples of operable classes of particulate mineral extenders. Thepreferred extenders are the porous, absorptive, preformed particles suchas preformed and screened particulate attapulgite or heat expanded,particulate vermiculite, and the finely-divided clays such as kaolinclays, hydrated attapulgite or bentonitic clays.

These extenders are sprayed or blended with the active ingredient toform the phytotoxic granules.

The mineral particles which are used in the granular phytotoxiccompositions of this invention usually have a size range of 10 to 100mesh, but preferably such that a large majority of the particles havefrom 14 to 60 mesh with the optimum size being from 20 to mesh.

Clay having substantially all particles between 14 and 80 mesh and atleast about80 percent between 20 and 40 mesh is particularly preferredfor use in the present granular composition. The term mesh as usedherein means U.S. Sieve Series.

The granular phytotoxic compositions of this invention generally containfrom about 5 parts to about 30 parts by weight of active ingredient per100 parts by weight of clay and 0 to about 5 parts by weight of surfaceactive agent per 100 parts by weight of particulate clay. The preferredplant growth regulant granular compositions contain from about l0 partsto about 25 parts by weight of active ingredient per 100 parts by weightof clay.

The phytotoxic compositions of this invention can also contain otheradditaments, for example, fertilizers, other phytotoxicants, plantgrowth regulants, pesticides and the like used as adjuvant or incombination with any of the above-described adjuvants. Chemicals usefulin combination with the active ingredients of this invention include forexample, triazines, ureas, carbamates, acetamides, acetanilides,uracils, acetic acids, phenols,

thiolcarbamates, triazoles, benzoic acids, nitriles and the like suchas:

3-amino-2,5-dichlorobenzoic acid 3-amino-l ,2,4-triazole2-methoxy-4-ethylamino-6-isopropylamino-s-triazine2-chloro-4-ethylamino-6-isopropylamino-s-triazine2-chloro-N,N-diallylacetamide 2-chloroallyl diethyldithiocarbamateN,-(4-chlorophenoxy) phenyl-N,N-dimethylurea isopropylM-(3-chlorophenyl)carbamate 2,2-dichloropropionic acidS-2,3-dichloroallyl N,N-diisopropylthiolcarbamate2-methoxy-3,-dichlorobenzoic acid 2,6-dichlorobenzonitrile6,7-dihydrodipyrido( l,2-a:2,1'-c)-pyrazidiinium salt 3-(3,4-dichlorophenyl)-l l -dimethylurea 4,6-dinitro-o-sec-butylphenol2-methyl-4,6-dinitrophenol ethyl N,N-dipropylthiolcarbamate2,3,6-trichlorophenylacetic acid 5-bromo-3-isopropyl-6-methyluracil 3-(3 ,4 -dichlorophenyl l -methoxyl -methylurea2-methyl-4-chlorophenoxyacetic acid 3-(p-chlorophenyl)-1,l-dimethylureal-butyl-3-( 3,4-dichlorophenyll -methylurea I N-l-naphthylphthalamicacid 1,1 '-dimethyl-4,4-bipyridinium salt2-chloro-4,6-bis(isopropylamino)=s-triazine2-chloro-4,6-bis(ethylamino)-s-triazine 2,4-dichlorophenyl-4-nitrophenylether alpha,alpha,alpha-trifluoro-2,6-dinitro-N,N dipropyl-p-toluidineS-propyl dipropylthiolcarbamate 2,4-dichlorophenoxyacetic acid2,6-diethyl-N-methoxymethyl-2-chloroacetanilid'e Fertilizers useful incombination with the active ingredients include, for example, ammoniumnitrate,

urea, potash, and superphosphate. Other useful additaments includematerials in which plant organisms take root and grow such as compost,manure, humus, sand and the like.

When operating in accordance with the present invention, effectiveamounts of the active ingredient are applied to aboveground portions ofplants. The application of liquid and particulate solid phytotoxiccompositions to above-ground portions of plants can be carried out byconventional methods, e.g. power dusters, boom and hand sprayers andspray dusters. The compositions can also be applied from airplanes as adust or a spray because of their effectiveness at low dosages.

The application of an effective amount of the active 'ingredient of thecompositions of this invention to the plant is essential and criticalfor the practice of one embodiment of the present invention. The exactamount of active ingredient to be employed is dependent upon theresponse desired in the plant as well as such other factors as the plantspecies and stage of development thereof, the specific soil and theamount of rainfall as well as the specific active ingredient employed.In foliar treatment for the modification of vegetative growth, theactive ingredients are applied in amounts from about 1 to about 50 ormore pounds per acre. It is believed that one skilled in the art canreadily determine from the teachings of this specification, includingexamples, the approximate application rate for best results.

dichlorobenzothiohydroxamic acid and benzothiohydroxamic acid.

2. The method of claim 1 wherein the thiohydroxamic acid is4-nitrobenzothiohydroxamic acid.

3. The method of claim 1 wherein the thiohydroxamic acid is3,4-dichlorobenzothiohydroxamic acid.

4. The method of claim 1 wherein the thiohydroxamic acid isbenzothiohydroxamic acid.

2. The method of claim 1 wherein the thiohydroxamic acid is4-nitrobenzothiohydroxamic acid.
 3. The method of claim 1 wherein thethiohydroxamic acid is 3,4-dichlorobenzothiohydroxamic acid.
 4. Themethod of claim 1 wherein the thiohydroxamic acid is benzothiohydroxamicacid.